Fuel injection system



July 4, 1961 R. J. POWELL ET AL 2,991,055

FUEL INJECTION SYSTEM Filed April 1, 1957 2 Sheets-Sheet 1 INVENTORSROBERT J. POWELL BY JAMES E. CHAMPION ATTOR July 4, 1961 R. J. POWELL ETAL 2,991,055

FUEL. INJECTION SYSTEM Filed April 1, 1957 2 Sheets-Sheet 2 I FIG-.3.

52 gg 4s K W 390 4 39b l5 VJ 5| 59 580 set) INVENTORS ROBERT J. POWELL YJAMES E.CHAMP|ON ATTO S FUEL INJECTION SYSTEM Robert J. Powell and JamesE. Champion, Muskegon, Mich, assignors to Continental MotorsCorporation, Detroit and Muskegon, Mich., a corporation of Vir- FiledApr. 1. 1957, Ser. No. 649,716

This invention relates to fuel injection systems for internal combustionenginesfand more particularly to a continuous flow fuel injection systempreferably adapted foruse' in mutli-cylinder type engines and having asimplified fuel pressure delivery system.

Continuous flow fuel injection systems are desirable for multi-cylinderengines,particularly for aircraft, because of the relative simplicity ofconstruction and operation and the fact that such systems reduce icing.However, these systems heretofore failed to meet efiicient and reliableperformance standards without being made correspondingly complex. Thefuel metering .valve and associated components are particularlysusceptible to failure and variations in operation the more complex theybecome, as well as being highly expensive and. dilficult to adjust andrepair.

Another complication that arises in continuous flow fuel injecionsystems is the fact that variations in fuel pump inlet pressure makesthe maintenance of a uniform maximum fuel pump delivery pressure verydifiicult.

An object of the present invention is to provide effective fuelinjection for internal combustion engines by constructing a continuousflow fuel pressure delivery and metering system.

Another object of the invention is to improve fuel injection byproviding a rugged and simplified fuel injection system operable todeliver and meter fuel efficiently under all engine operatingconditions.

A further object of the invention is to provide an inexpensive anddependable fuel injection system for internal combustion engines byconstructing a simplified continuous flow metering valve operable tometer fuel effectively in response to engine throttle operation andprovided with means fonmaintaining a substantially uniform maximum fuelpump delivery pressure to the metering valve irrespective of fuel pumpinlet pressure variations.

'A still further object of the invention is to improve fuel injection byproviding a relief valve associated with the fuel pump delivery outletand operable to maintain a substantially uniform maximum deliverypressure irlivery pressure caused by variation in pump inletpressure.

For a more complete understanding of the invention, reference may be hadto the accompanying drawings illustrating" a preferred embodiment of theinvention in which like characters refer to like parts throughout theseveral views and in which i r FIG. 1 is a diagrammatic view of apreferred fuel in- 2,991,055 Patented July 4, 1961 valve structure 15, afuel distributing manifold 16, and a plurality of fuel injectors 17adapted to inject fuel into an air intake manifold 18, an injector beinginstalled for each engine cylinder air intake. An air throttle valve 19is adjustably disposed in an air intake section 18a of the manifold 18.and is preferably connected by suitable linkage 20 to the fuel meteringvalve 15.

Fuel is pumped from the tank 10 through pipes or conduits 25 and 26 intothe intake side of the pump assembly 14. Fuel under pressure is thenpumped through a conduit 28 to the fuel meteringvalve 15, where ametered amount of fuel is delivered to the fuel manifold 16 through aconduit 24 for distribution to the injectors 17 in accordance withengine fuel requirements as determined by. the operation of the throttle19.

For proper mixture control, a'portion of the fuel may be spilled fromthe metering valve 15 to return through a conduit 29 for recirculationto the pump assembly 14.

A preferred construction for the fuel injection metering valve structure15 is illustrated in FIG. 3 as comprising a valve housing 35 having afuel inlet port 36 adapted for connection with the outlet side of thepump assembly 14 through the conduit 28, a fuel delivery outlet port 37adapted for connection with the fuel distributing manifold 16 throughthe conduit 24, and a fuel spill outlet port 38 adapted for connectionwith the intake side of the pump assembly 14 through the conduit 29 andthe vapor separator 55.

A longitudinal bore 39 extends through the housing 35, and is separatedby a fixed or stationary divider element 40 into two bore sections 39aand 3%. A fuel metering passage 41in the divider element 40 is open onopposite faces thereof respectively to the bore sections 39a and 39b.

A fuel mixture control valve member 42 is rotatably supported in thebore section 39a and abuts the face of the fixed divider element 40. Anadjustable fuel metering control valve member 43 is rotatably supportedin the bore section 3912 and abuts the opposite face of the dividerelement 40. The metering control valve member 43 is provided with alever 44 which is adapted to be operatively connected to the linkage 20shown in FIG. 1 for operation relative to operation of the throttlevalve 19. The control valve members 42 and 43 are preferably axiallyaligned in the bore 39.

An annular groove 45 is provided in the valve member 42 and iscontinuously openly connected with a fuel inlet passage 46 indicated bydotted lines in FIG. 3, provided in the housing 35 and connected withthe inlet port 36. The passage 46 extends from the inlet port 46 up wardbehind the member 42 shown in FIG. 3 and interice sects the side of thebore 39 hidden from view by the member 46. A groove 47 is provided onthe end of the valve member 42 which abuts the divider element 40 and afuel passage 48 in the valve member 42 connects the groove 47 with theannular groove 45. Fuel is thereby continuously conducted from the port36 through the passage 46 to the groove 45 and thence through thepassage 48 to the arcuate groove 47.

A fuel 'spill passage50 provided in the housing 35 connects the boresection 39a with the fuel spill outlet port 38. The groove 47 of thevalve member 42 is arranged so that angular adjustment thereof will openand close the spill passage 50 simultaneously as the metering passage 41is respeotively closed and opened.

In the rich mixture position of the valve member 42, the meteringpassage 41 is fully open and the spill passage 50 is fully closed. Afull flow of fuel under pressure is provided through the meteringpassage 41. In the lean mixture position of the valve member 42, themetering passage 41 is partially closed and the spill passage ispartially open. In the fuel cutoff position of the valve member 42, themetering passage 41 is fully closed and the spill passage 50 is fullyopen, providing for a full return of all the fuel to the intake side ofthe pump 14. A lever 51 is preferably provided on the outer end of thevalve member 42 for manual operation thereof or for connection to anydesired type of suitable actuating means.

The end of the metering control valve 43 which abuts the divider element40 is provided with a groove 52 which upon operation of the valve 43 inresponse to throttle operation, selectively opens and closes the fuelmetering passage 41 to provide effective metering of fuel. A fuelpassage 53 connecting the bore section 39b with the fuel delivery outletport 37 is arranged to be open to the groove 52.

The fuel pump assembly 14 as illustrated diagrammatically in FIG. 1preferably includes a vapor separator 55 connected with the conduit 26,a fuel pump 56 having an inlet 56a connected with the vapor separator 55and an outlet 56b connected with the conduit 28 and through a restrictedorifice 57 with an inlet 58a of a relief valve 58. A relief valve outlet58b is connected through a suitable passage 59 with the vapor separator55 and thence with the inlet 56a of the pump 56. The vapor separator 55in essence is a chamber in which the fuel from conduits 26 and 59 isangular-1y whirled before discharging into the passage leading to theintake 56a of the pump '56. Vapor thus collects in the center of thechamber and is withdrawn by means of a venturi 55a through which fuelunder pressure passes from a passage 55b to a conduit 55c leading to thefuel tank 10. A bypass passage 55d is also provided. The vapor separatoritself is the subject matter of our copending application Serial No.640,044 and is not illustrated here in detail.

As may be seen from FIG. 2, the relief valve 58 comprises a two-parthousing 59 preferably having a valve member 60. A fuel pressure inletchamber 61 connected with the inlet 58a is opened and closed on axialmovement of the valve member 60 shown in open position to relieve excessfuel pressure into an outlet fuel chamber 62, connected with the outlet58b.

An atmospheric pressure chamber 63 is separated from the outlet fuelchamber 62 by a diaphragm member 64 connected between the valve member60 and the housing 59. The diaphragm member 64 has an effective areaequal to the effective area of the valve member 60. A spring element 65tends to urge the valve member 60 into the closed position. Theatmospheric pressure chamber 63 is connected with atmosphere preferablythrough a port 66, so that fuel pump inlet pressure in the chamber 62 iseffectively balanced against atmospheric pressure. Thus fuel pump inletpressure variations are effectively nullified and will not affect fuelpump delivery pressure, which remains at a substantially uniform maximumvalue during normal system operation, this maximum value beingdetermined as in the usual relief valve by the pressure exerted by thespring 65. Since the fuel pump delivery is generally always greater thanengine requirements, the relief valve member 61 will be normallycontinuously open, permitting excess fuel to pass back to the inlet sideof the pressure pump 56. The restricted orifice 57 is provided to set upresistance to undesirable increased fuel flow through the relief valve58 in response to any increased engine speed which increases fuel pumpdelivery pressure when there is no change in the regulated outlet areaof the fuel metering passage 41 of the fuel metering valve 15.

We claim:

1. 'A fuel injection system for direct continuous injection of fuel intothe air induction system of an internal combustion engine, said airinduction system having an air induction manifold and an adjustable airthrottle valve associated therewith for varying engine speed, said fuelinjection system comprising a fuel supply source, a fuel pressure pumpadapted to'be driven by said engine, said pump assembly having an intakeconnected with said fuel supply source a delivery outlet and, a fuelmetering valve structure having an inlet connected with said pumpdelivery outlet and a regulatablefuel discharge outlet connected withsaid air induction system downstream of said throttle valve, a meteringvalve means operatively .connected with said throttle valve to vary theopening of said discharge outlet in response to throttle valveoperation, a fuel pressure relief valve associated with said fuel pumpdelivery outlet, said relief valve constructed and arranged to normallymaintain a substantially uniform maximum fuel pump delivery pressureirrespective of variations in fuel pump intake pressure, and arestrictedorifice of fixed predetermined size disposed ahead of saidrelief valve to restrict increased fuel flow to said relief valve on anincrease of fuel pump delivery while said [fuel metering dischargeoutlet opening remains substantially constant, said relief valvecomprising valve actuating means connected with atmosphere and with saidpump intake and operable to balance pump intake pressure againstatmospheric pressure to nullify the effect of pump intake pressure onpump delivery pressure.

i 2. A fuel injection system for direct continuous injection of fuelinto the air induction system of an internal combustion engine, said airinduction system having an air induction manifold and an adjustable airthrottle valve associated therewith for varying engine speed, said fuelinjection system comprising a fuel supply source, a fuel pressure pumpadapted to be driven by said engine; said pump assembly having adelivery outlet and an intake connected with said fuel supply source, afuel metering valve structure having an inlet conected with said pumpdelivery outlet and a regulatable fuel discharge outlet connected withsaid air induction system downstream of said throttle valve, a meteringvalve means operatively connected with said throttle valve to vary theopening of said discharge outlet in response to throttle valveoperation, a fuel pressure relief valve associated with said fuel pumpdelivery outlet, said relief valve constructed and arranged to normallymaintain a substantially uniform maximum fuel pump delivery pressureirrespective of variations in fuel pump intake pressure, and arestricted orifice of fixed predetermined size disposed ahead of saidrelief valve to restrict increased fuel flow to said relief valve on anincrease of fuel pump delivery while said fuel metering discharge outletopening remains substantially constant, said relief valve comprising avalve housing structure having an inlet openingly connected with saidorifice and an outlet openly connected with said fuel pump intake, valvemeans in said housing and normally operable to maintain the aforesaidmaximum pump delivery pressure, said valve means having a pressureresponsive element connected between said valve outlet and atmosphereand operable to nullify the effect of pump intake pressure on pumpdelivery pressure.

References Cited in the file of this patent UNITED STATES PATENTS1,376,201 Harris Apr. 26, 1921 2,136,959 Winfield Nov. 15, 19382,759,468 Powell Aug. 21, 1956 2,785,669 Armstrong Mar. 19, 19572,791,205 Platner et a1. May 7, 1957 2,813,522 White et al Nov. 19, 19572,816,745 McCain Dec. 17, 1957 2,849,999 Morris Sept. 2, 1958 2,851,026Dah-l et 'al Sept. 9, 1958

